Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest. The most common use of pesticides is as plant protection products (also known as crop protection products), which in general protect plants from damaging influences such as weeds, diseases or insects. This use of pesticides is so common that the term “pesticide” is often treated as synonymous with “plant protection product”, although it is in fact a broader term, as pesticides are also used for non-agricultural purposes.
A pesticide is generally a chemical or biological agent (such as a virus, bacterium, antimicrobial or disinfectant) that through its effect deters, incapacitates, kills or otherwise discourages pests. Target pests can include insects, plant pathogens, weeds, mollusks, birds, mammals, fish, nematodes (roundworms), and microbes that destroy property, cause nuisance, spread disease or are vectors for disease. Although there are benefits to the use of pesticides, some also have drawbacks, such as potential toxicity to humans and other animals. According to the Stockholm Convention on Persistent Organic Pollutants, 9 of the 12 most dangerous and persistent organic chemicals are pesticides (J Obstet Gynecol Neonatal Nurs. 2010 January-February; 39 (1):103-10.).
From the lessons of the adverse side effects of chemical pesticides, the development of new chemical pesticides changes to high selectivity, low toxicity and safety for the environment as the main objective. However, this leads to the increasing of the cost and slowing the controlling effects. Until recently, the advances of the biotechnology and fermentation technology again affect the developing direction of pesticides. Biopesticide is expected to be the future main materials of plant protection.
There are more than 400 registered pesticides in Taiwan, but only about 50 are largely used. Owing to the “resistance” of the pests, many pesticides are abandoned from the registered companies and are not common in the market. In recent years, the introductions of new active ingredients of pesticide are slow and less than 10 are registered each year. Therefore, the pesticides should be used wisely to extend their life and to avoid the rapid existence of the resistance problem. In plant protection industry, it is thought that the rapid expansion of the “resistance” problem is related to the interaction of reagents having similar chemical structures and same mode of action. Rotationally using pesticides with different mode of actions is considered to be the most effective mean to prevent the resistance.
In fact, the development of a pesticide requires the investment of big amount of time and money. Using herbicides as an example, to develop a new herbicide, about 78,000 compounds would be screened, consuming 110 months and cost $150 million. So if we can maintain the effectiveness of the pesticides on targeting organisms and reduce the development of the resistance, the cost would be reduced and the environment would be protected.